The big question is whether home-field advantage can be established. In the NFC, the 49ers and Saints are considered better teams than their home opponents, but both teams travel into tough weather conditions. In the AFC, the Colts were 6-2 at home in the regular season, but they've shown signs of being vulnerable.

And then there's Green Bay. Since 2002, the Packers are 3-4 at Lambeau Field in the playoffs. That mark was 13-0 before '02.

Here are the top 10 trends from the wild-card round:

1. Preparing for the elements: One of the wild parts of the wild-card round is the weather. Cincinnati is expecting temperatures of 35 degrees along with rain and snow Sunday. Philadelphia will be dry and below freezing Saturday night. Green Bay is expecting the temperature to be zero with wind chills in the minus-teens. The only game without weather concerns is Kansas City playing indoors at Indianapolis. Which visiting quarterback will be most affected? Colin Kaepernick of the 49ers has played only two cold-weather games (defined as below 40 degrees), and he didn't do too badly. He completed 59.2 percent of his passes and had seven touchdowns along with six completions in excess of 25 yards. But Aaron Rodgers has 25 games' experience in the cold, and he's at home. Despite playing his career in balmy San Diego, Philip Rivers has put up good numbers in cold-weather games. He has 18 touchdown passes in 11 cold-weather games. Drew Brees knows the cold from when he played at Purdue. He has an impressive 65.1 completion percentage in his 11 cold-weather games, but his struggles on the road are well documented. Plus, in five games when the temperature was below 32 degrees, Brees' completion percentage dropped to 61 percent. He is 2-3 in those games with six interceptions.

Andrew Luck will likely see a more formidable Chiefs D than the one he faced in Week 16. AP Photo/Ed Zurga

2. Changing the game plan: Colts offensive coordinator Pep Hamilton knows he can't follow the exact game plan he used in a 23-7 victory over Kansas City in Week 16. In that game, Hamilton let Andrew Luck go to a no-huddle offense paced by quick, short passes. After two three-and-outs, the Colts overcame a 7-0 deficit and dominated the Chiefs. Luck knows a different strategy might be needed, even though the Colts are at home. In that game, the Chiefs were missing outside linebacker Justin Houston and lacked a consistent pass rush. Houston is back Sunday from his dislocated elbow, and the Chiefs hope linebacker Tamba Hali plays despite a knee injury. The Colts would like to run a balanced attack, which puts more pressure on halfback Trent Richardson. Richardson ran better down the stretch, but he finished the season with 563 yards and a 3.0-yard average. Chiefs coach Andy Reid rested his starters in Week 17 and hopes they are refreshed. Halfback Jamaal Charles says he feels better. The Chiefs lost five of their last seven regular-season games.

3. Will Kaepernick run wild? Kaepernick's running ability could be the key for the 49ers against the Packers. In last season's playoffs, the Packers were completely lost trying to stop Kaepernick, who ran for 181 yards. In the 2013 opener, Kaepernick ran for only 22 yards, but he passed for 412 yards and threw for three touchdowns. The 49ers won 34-28. The frozen-tundra conditions could force 49ers coach Jim Harbaugh to call more running plays with Kaepernick. The 49ers quarterback does his best against the Packers, but his two games against them were in San Francisco. Packers defensive coordinator Dom Capers spent the offseason trying to figure out ways to stop the read-option. After getting 176 yards on read-option runs against Green Bay in last season's playoffs, Kaepernick had only 10 on seven carries in the opener, according to ESPN Stats & Information.

4. Chip off a new block: The biggest mystery of the offseason was how Eagles coach Chip Kelly would do coming out of the University of Oregon with no NFL experience. He brought a fast-paced offense that was supposed to change the league. As it turned out, the NFC East didn't end up being as challenging as the Pac-12. Kelly rebounded from a 3-5 start to win the division and make the playoffs. Even though Kelly ended up starting Nick Foles after Michael Vick proved to be too banged up, the Eagles' offense was dynamic. The Eagles averaged 417.3 yards a game and set a franchise record for points scored (442). At Oregon, Kelly's offense dominated in time of possession, but in the pros, it surprisingly did not. In fact, the Eagles became the first offense since the 1991 Buffalo Bills to lead the league in rushing and finish last in time of possession (26:24 average).

5. Ending the playoff drought: The Bengals haven't won a playoff game since the 1990 season, even though Marvin Lewis has the team in the playoffs for a third consecutive year. If they can't win Sunday, something must be wrong. The Chargers will be a tough opponent, because Rivers can beat any team, particularly on the road. Still, the Bengals are 8-0 at home and won their regular-season home games by an average of 17.6 points. They have the deepest offensive group of weapons in football. Their defense ranked third in the league. The pressure falls on quarterback Andy Dalton, who is 0-2 in the playoffs. Dalton tends to complete the longer passes at home. On the road, the longer passes often don't connect. Since 1990, the Bengals are 0-5 in playoff games. The Chiefs, who visit the Colts, are tied with the Detroit Lions for the longest streak of playoff games without a win (seven).

6. Big game for Brees: Saturday night could be a defining game for the Saints' Pro Bowl quarterback. Sean Payton is aware of the Saints' struggles away from the Superdome -- New Orleans was 3-5 on the road, and Brees' numbers dipped significantly in those contests. The Saints' prolific attack went from 34 points a game at home to 17.6 on the road, and the turnover ratio flipped from plus-6 to minus-6. Brees had nine of his 12 interceptions on the road. The Eagles' defense is beatable -- particularly against the pass, which could help Brees as he tries to deliver the franchise's first road playoff win (0-5 all time) in what could be tough conditions.

7. Blindside concerns: Most of the teams participating in this weekend's contests are sound at left tackle, the most important position along the offensive line for right-handed quarterbacks. Branden Albert is back from a knee injury as the Chiefs' left tackle. Jason Peters is a Pro Bowler for the Eagles. The Bengals' line surprisingly got better when Pro Bowl-caliber left tackle Andrew Whitworth moved to left guard, and it has seen solid play from Anthony Collins at left tackle. Indy's Anthony Castonzo allowed only four sacks at left tackle protecting Luck, while Joe Staley had another big season for the 49ers. The Saints, Chargers and Packers haven't had as much success with their tackles. King Dunlap fought injuries all season and had only 11 starts for San Diego, and David Bakhtiari gave up 7.5 sacks in Green Bay. New Orleans' Terron Armstead may be the biggest question mark of the trio, as he faces an Eagles pass rush led by Trent Cole and his team-best 8.0 sacks. Payton went to the rookie after getting tired of poor blocking by Charles Brown, who yielded eight sacks in 14 starts. Armstead hasn't fared much better, giving up an average of a sack a game in his starts. His blocking will be critical in buying time for Brees to get off longer passes -- an already arduous task on the road.

8. Can the Colts put Charles on hiatus? Philadelphia's LeSean McCoy led the NFL in rushing, but Charles might have been the more valuable player to his team's offense. Reid rested Charles in Week 17, but with 1,980 yards he still ended up accounting for 35.3 percent of the Chiefs' offense and scored an NFL-best 19 TDs. The Colts couldn't contain him during their Week 16 contest, as he gashed Indy for 106 yards on 13 carries and caught five passes for 38 yards. However, due to a large second-half deficit, K.C. couldn't get Charles his normal amount of touches down the stretch.

With Aaron Rodgers back in the saddle, the Packers could make a lot of noise in the NFC. Scott Strazzante/Chicago Tribune/MCT via Getty Images

9. The return of Rodgers: It's still amazing to think the Chicago Bears and Detroit Lions let the Packers win the NFC North. During Rodgers' seven-game absence, the Packers managed only two wins and a tie, but it was enough to keep pace in the division race. His Week 17 return vaulted Green Bay to a win in Chicago and an 8-7-1 final record that was good enough to grab the division crown. With Rodgers under center, the Packers went 6-3 as he completed two-thirds of his passes and averaged 8.7 yards per throw. Rodgers beats teams in a multitude of ways: He has one of the league's strongest, most accurate arms, and if his receivers are covered, he can run for first downs. His return makes the Packers a dangerous team in the NFC.

10. Chargers are the true wild cards: In recent years, the Super Bowl champ has been a team that gets hot down the stretch. While that might be a stretch for Mike McCoy and the Chargers, they are certainly hot at the right time. San Diego has won four in a row, and Rivers has been as hot as any quarterback in December. Of the playoff participants, only the 49ers finished the season with more consecutive wins than the Bolts. One potential hurdle is Sunday's start time of 1 p.m. ET, which puts the players' internal clocks at 10 a.m. The Chargers have done well this year in both East Coast games and early starts, but it's been tough for them to get going in the first quarter. Rivers, though, has been a great road quarterback. He completed 71.5 percent of his passes with 15 touchdown throws on the road this season.